Analysis of morphology of adrenal pheochromocytoma as regards their potential malignancy

BACKGROUND: Adrenal pheochromocytoma are diagnosed the most often in patients with arterial hypertension or with thyroid medullar cancer and suspicion of MEN II syndromes. The aim of the study is to analyse the morphology of pheochromocytomas on the basis of Pheochromocytoma of the Adrenal Gland Scaled Score (PASS) in order to estimate their potential malignancy. MATERIAL AND METHODS: Forty tumours were subjected to analysis. Mean patients age was 45.2+/-13.4 years. The diagnosis of pheochromocytoma was establish before surgery in 87.5%. 12.5% of patients were referred to surgery on the basis of tumour diameter (range 70 to 102 mm). In 20.0% of patients MEN II syndromes were diagnosed. RESULTS: In pathological examination benign pheochromo-cytoma was diagnosed in 39 presented patients. In 1 cases malignant form of pheochromocytoma was diagnosed on the basis of lymph nodes metastases. Number of points in PASS was >or=4 in 9 of 40 tumours (22.5%). Among 35 patients operated on more than 12 months ago 2 patients died: 1 patient with malignant pheochromocytoma (PASS=8 points) and 1 patient with MEN IIA syndrome (due to disseminated thyroid medullar cancer). In remaining 7 observed patients with PASS>or=4 points neither recurrence nor metastases were diagnosed within the period of observation (13-90 months). In 1 out of patients with PASS<4 points a local recurrence was surgically removed 82 months after primary operation. CONCLUSION: Analysis of pheochromocytoma in PASS is only of rough character and does not allow for clear-cut histological diagnosis of benign and malignant tumours. The only unquestionable criterion of pheochromocytoma's malignancy remain metastases.     

Estimation of sodium/iodide symporter gene expression (NIS) in thyroid cancer by RT-PCR technique (preliminary study)

NIS gene is located on chromosome 19 and encodes 643 amino acid protein. It belongs to membrane Na+ dependent glucose symporter proteins family. In normal thyroid is located in basolateral membrane of thyreocyte. It plays a main role in concentrating of iodine in thyreocyte and thus in thyroid hormones synthesis. It was proved that NIS expression influences effectiveness of radioactive iodine therapy in well-differentiated thyroid cancers. The aim of this study was to estimate the NIS expression and its dependence with gender, age and stage in thyroid papillary and follicular cancers. The frozen sections of tissue were used as a source of tumor RNA. RT-PCR technique was employed for NIS expression analysis. We did not find dependence between the presence of NIS expression in investigated thyroid cancers and stage of disease estimated according to TNM classification. We also did not find dependence between NIS expression and gender or sex of the patients. Our results suggest that there is no dependence between NIS expression and iodine uptake.     

Lymph node metastases of papillary thyroid cancer in immunohistochemical and molecular examination--preliminary report

BACKGROUND: Total thyroidectomy with lymphadenectomy is the most typical operation in a case of papillary thyroid cancer. Range of lymph node resection still remains a matter of controversy. In some publications treatment of lymph node metastases doesn't affect survival, so only selective lymph node resection is the extended enough operation. The others remark that, local relapse- the worst prognostic factor, appears the most often in the lymph nodes, so they suggest more aggressive treatment. To solve that problem we try to find more sensitive methods to examine lymph nodes. AIM: To compare the results of detection lymph node metastases of papillary thyroid cancer by immunohistochemistry with the results of RT- PCR for thyroglobulin (Tg) mRNA. MATERIAL AND METHODS: Each of one hundred eighty four cervical lymph nodes obtained from 24 patients, operated in our Department was divided into 2 halves: one was used for conventional histopathology and immunohistochemistry, the other part was investigated by RT- PCR for Tg mRNA. Immunohistochemical staining for Tg was performed on formalin-fixed, paraffin-embedded sections with anti-Tg antibodies. RESULTS: According to routine, histopathological examination 8 (33.5%) patients had involved lymph nodes. One hundred correspondence of the results of immunohistochemistry and histopathology was observed. We obtained different results of examination of the lymph nodes in 6 (25%) patients. In four patients (16.7%) RT-PCR was more sensitive in detection of positive lymph nodes, in two patients (8.3%) it revealed less metastasized lymph nodes than immunohistochemistry. The remaining 18 patients didn't have any differences, fourteen (58.3%) of them had the negative lymph nodes and four (16.7%) had positive, the same lymph nodes in all examinations. Finally, according to RT-PCR 10 (41.7%) of the patients had metastasized lymph nodes. COCLUSION: Tg RT-PCR is a sensitive method of detection of papillary thyroid cancer cells and may help to detect the metastases of papillary thyroid cancer in regional lymph nodes.     

Metabolic responses of Lemna minor to lead ions II. Induction of antioxidant enzymes in roots

Duckweed Lemna minor L. was grown on Wang culture medium supplemented with lead ions for 24 hours. Metal was tested at 1.5, 3 and 6 mg·dm⁻³ concentrations. The response of antioxidant enzymes, such as superoxide dismutase, catalase and peroxidase in lead-treated roots of duckweed was investigated. Lead ions had no effect on the spectrum of catalase and peroxidase isoenzymes while a new isoform of superoxide dismutase appeared on the Pb treated roots. A lead-depended increase in activities of superoxide dismutase and peroxidase was observed, whereas catalase activity was maintained at relatively constant values at lower lead concentrations and then decreased markedly below control level.     

Age-related difference in bioenergetics of lung and heart mitochondria from rats exposed to ozone

Bioenergetics of isolated lung and heart mitochondria from adult and aged rats were examined in the presence of glutamate (NAD-linked substrate) or succinate + rotenone (FAD-linked substrate) following ozone exposure (3.0 ppm, 8 hr). In controls, several differences were observed between adults and aged in both organ preparations. Following exposure, all bioenergetic parameters were decreased significantly in lung preparations from both adult and aged rats. In heart mitochondria, the respiration rates in state 3 and in uncoupled state, and the ADP/O ratio were decreased significantly in both exposed age groups. The respiratory control ratio (RCR) was decreased significantly only in the aged exposed rats. These results suggest that acute exposure to high levels of ozone alters energy production in both lung and heart mitochondria of adult and aged rats.     

A Study of the Influence of Charged Residues on β-Hairpin Formation by Nuclear Magnetic Resonance and Molecular Dynamics

Chain reversals are often nucleation sites in protein folding. The β-hairpins of FBP28 WW domain and IgG are stable and have been proved to initiate the folding and are, therefore, suitable for studying the influence of charged residues on β-hairpin conformation. In this paper, we carried out NMR examination of the conformations in solution of two fragments from the FPB28 protein (PDB code: 1E0L) (N-terminal part) namely KTADGKT-NH₂ (1E0L 12–18, D7) and YKTADGKTY-NH₂ (1E0L 11–19, D9), one from the B3 domain of the protein G (PDB code: 1IGD), namely DDATKT-NH₂ (1IGD 51–56) (Dag1), and three variants of Dag1 peptide: DVATKT-NH₂ (Dag2), OVATKT-NH₂ (Dag3) and KVATKT-NH₂ (Dag4), respectively, in which the original charged residue were replaced with non-polar residues or modified charged residues. It was found that both the D7 and D9 peptides form a large fraction bent conformations. However, no hydrophobic contacts between the terminal Tyr residues of D9 occur, which suggests that the presence of a pair of like-charged residues stabilizes chain reversal. Conversely, only the Dag1 and Dag2 peptides exhibit some chain reversal; replacing the second aspartic-acid residue with a valine and the first one with a basic residue results in a nearly extended conformation. These results suggest that basic residues farther away in sequence can result in stabilization of chain reversal owing to screening of the non-polar core. Conversely, smaller distance in sequence prohibits this screening, while the presence oppositely-charged residues can stabilize a turn because of salt-bridge formation.     

Synthesis of 3′-N-Substituted 3′-Amino-3′-Deoxythymidine Derivatives

Abstract

A series of 3′-N-substituted 3′-amino-3′-deoxythymidine derivatives with alkyl, alkenyl and alkylaryl substituents was synthesized by two methods. The first method involved the reaction of 1-(2,3-dideoxy-3-0-mesyl-5-0-trityl-β-D-threo-pentofuranosyl)thymine with an appropriate amine. In the second method, 3′-amino-5′-0-trityl-3′-deoxy-thymidine served as a synthetic precursor which was reacted with an appropiate aldehyde or ketone followed by sodium borohydride reduction. An improved synthesis of 3′-amino-3′-deoxythymidine from 3′ -azido-5′-0-trityl-3′-deoxythymidine using sodium borohydride was also described.